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排序方式: 共有606条查询结果,搜索用时 0 毫秒
91.
Kikuo Matsui Hideki Shimada Takashi Sasaoka Hirofumi Furukawa Takeshi Ueda Atsuko Yabuki 《国际露天开采、回填与环境杂志》2013,27(3):185-204
Conventional highwall mining extracts coal with an auger machine or a continuous miner from exposed seams at the base of opencut or strip operations. However, under poor strata and high stress conditions, highwall mining cannot be conducted due to pillar and roof failures. In such cases, punch highwall mining is more effective than the conventional highwall mining. This paper describes conventional highwall mining and punch highwall mining systems and discusses the stability of the highwall due to punch highwall mining at opencut coal mines. 相似文献
92.
93.
Computational Study of Nonadiabatic Wave Patterns in Smouldering Combustion under Microgravity 下载免费PDF全文
Ekeoma Rowland Ijioma Hirofumi Izuhara Masayasu Mimura & Toshiyuki Ogawa 《East Asian journal on applied mathematics.》2015,5(2):138-149
We numerically study a thermal-diffusive model for smouldering combustion
under microgravity with convective heat losses. In accordance with previous experimental
observations, it is well known that porous materials burning against a gaseous oxidiser
under microgravity exhibit various finger-like char patterns due to the destabilising
effect of oxidiser transport. There is a close resemblance between the pattern-forming
dynamics observed in the experiments with the mechanism of thermal-diffusive instability,
similar to that occurring in low Lewis number premixtures. At large values of the
Lewis number, the finger-like pattern coalesces and propagates as a stable front reminiscent
of the pattern behaviour at large Péclet numbers in diffusion-limited systems. The
significance of the order of the chemical kinetics for the coexistence of both upstream
and downstream smoulder waves is also considered. 相似文献
94.
A dynamic electronic speckle pattern interferometry method is applied to investigate thermal expansion of a joint material (ceramic-stainless steel) as a practical industrial object. The speckle interference signal is considered in the temporal domain and the phase is analyzed by the Hilbert transform method. Errors caused by the bias and modulation variations over the phase values are first examined by numerical simulation. Two experiments are performed with in-plane and out-of-plane sensitive systems to study the 3D deformation field thoroughly. The deformation field showed clearly the difference between the thermal expansions of the stainless steel and ceramic. It was also revealed that the boundary of materials and its vicinity suffer very large thermal strain due to the significantly large difference in the linear coefficient of thermal expansions. 相似文献
95.
Kondo A Noguchi H Ohnishi S Kajiro H Tohdoh A Hattori Y Xu WC Tanaka H Kanoh H Kaneko K 《Nano letters》2006,6(11):2581-2584
Crystal-to-crystal transformation from a 3D interpenetrated-type MOF {[Cu(BF(4))(2)(bpy)(H(2)O)(2)] (bpy)} (1) to a 2D square-grid-type [Cu(BF(4))(2)(bpy)(2)] (2) (bpy = 4,4'-bipyridine) was observed. It was derived from dehydration and confirmed by in situ FT-IR, TG, and elemental analysis. Moreover, we elucidate the novel expansion/shrinkage dynamic modulation of 2 triggered by clathrate formation with gas molecules. 相似文献
96.
97.
Yokoyama Y Kawashima H Kanie H 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2006,53(9):1551-1553
The electrical properties of an X-cut, length-extensional mode quartz crystal resonator of a cut angle theta around the X-axis were calculated by a variational method using stresses as trial functions. Analytical expressions of stresses were estimated by a linear regression on a cut angle best-fit to the results of finite-element method. The calculated dependence of the capacitance ratio on the cut angle was consistent with the measured results. 相似文献
98.
The atomic-bridging type negative oxide charge in SiO2 is investigated using the Fe-contaminated (001) surface of n-type Si wafers. The investigation is done on the basis of a chemical analysis and a method in which the frequency-dependent alternating current (AC) surface photovoltage (SPV) is measured. At room temperature, an AC SPV appears and gradually increases, saturating after approximately one day (with an Fe concentration on the Si surface of 4.0 × 1013 atoms/cm2). The AC SPV eventually becomes inversely proportional to frequency except at very low frequencies (< 10 Hz) corresponding to weak or strong inversion, indicating that the negative Fe induced oxide charge appears in the form of a (FeOSi)− network. Also, in Fe-contaminated n-type Si(001) surfaces thermally oxidized at between 550 and 650 °C for 60 min, strong inversion is unquestionably observed, proving that the (FeOSi)− network survives and that most of the added Fe has segregated into the region closest to the surface of the thin SiO2 film. At 850 °C and/or for long oxidation times, the AC SPV decreases and ultimately disappears, implying that the (FeOSi)− network has collapsed and may have changed into Fe2O3. A model for the metal-induced negative oxide charge in the conventional oxide charge diagram is proposed. 相似文献
99.
Tanaka H Hong L Fukumori M Negishi R Kobayashi Y Tanaka D Ogawa T 《Nanotechnology》2012,23(21):215701
Nanoparticles of N,N'-bis(n-alkyl)tetracarbonatenaphthalenediimide (NDI) were adsorbed on single-walled carbon nanotube (SWNT) wires dispersed on a SiO(2) substrate. The electrical properties were measured along the long axis of the SWNTs, and in all cases through the nanoparticles showed rectification in semiconducting I-V curve. The plateau width of the I-V curve through the NDI nanoparticles on metallic SWNTs decreased as the particle size increased, while the rectification ratio increased. The conduction mechanism was changed from tunneling conduction to Schottky-like conduction and their boundary is at about 3 nm diameter. 相似文献
100.
Yong-Jun LiuYan Cheng Tomonori OhbaKatsumi Kaneko Hirofumi Kanoh 《International Journal of Hydrogen Energy》2011,36(20):12902-12908
A nanocrystalline composite of lithium nitride and lithium carbide was synthesized through melt infiltration of lithium metal into the mesopores of carbon aerogels followed by nitrogenation with nitrogen gas. The structure, surface properties, and morphology of the prepared samples were examined by XRD, N2 adsorption at 77 K, FE-SEM, FE-TEM, and TPD/MS. It was found that some of the lithium metal reacted with the carbon to form lithium carbide, and some of the lithium metal was transformed into lithium nitride by nitrogenation, yielding a composite of lithium nitride and lithium carbide. Relative to the bulk lithium nitride, the lithium nitride in the composite showed a significantly enhanced sequential hydrogen absorption capacity and a lowered temperature of hydrogenation/dehydrogenation. 相似文献